Tying weights and shape debugging

Questions
1

I have a racing dataset of which each competitor has 155 features and there are 10 competitors per race. I have approximately 100000 races worth of data. I wish to predict the winner.

The X dataset is 100000x1550 (by concatenating the 155 features). I want to tie the weights so that the same weights are applied to each competitor. The model that I have created is as follows:

    n_features = 155
    n_competitors = 10
    init_1 = np.random.randn(n_features, 1)*np.sqrt(2/(1 + n_features))

    with pm.Model() as linear_model:
        w1 = pm.Normal('w1', 0, sd=1, shape=(n_features, 1), testval=init_1)
        w1_repeat = pm.math.block_diagonal([w1]*n_competitors)
        act_out = tt.nnet.softmax(tt.dot(X, w1_repeat))
        out = pm.Categorical('out', act_out, observed=Y)

Y is a one hot encoded, so that it’s size is 100000x10.

I’m getting the error:

IndexError: shape mismatch: indexing arrays could not be broadcast together with shapes (100000,) (100000,10)

The first question is, is there something I’m doing wrong? Especially with the block diagonal part (this is how I tie weights).

The second question is, how would I get the shape of a variable? w1_repeat.shape simply spits out Shape.0.

Incase some needs a test X and Y;

N = 100000
n_features = 155
X = np.random.rand(N, n_features*10)
Y = np.zeros((N,10))
Y[:,0] = 1
2

I usually check the shape by doing w1_repeat.tag.test_value.shape

The observed of a Categorical distribution should be a vector, replace the one hot encoded Y with np.where(Y==1)[1] should work.

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